1. Field of the Invention
This invention relates generally to cotton gins and in particular to an improved cotton gin roller bar.
2. Description of the Prior Art
The conventional cotton gin includes a series of circular saws arranged at relatively close spacings along a rotatable shaft, the saws operating between a series of gin bars spaced to provided minimum clearance for the saws and to permit passage of cotton fibers impaled on the saw teeth, and rejecting the seed as the lint fiber is detached therefrom. A limiting factor in the use of the gin bar and rotary saw blade combination is the excessive wear on the gin bar at the ginning point caused by the abrasive action of particulated material such as grit which clings to the cotton fibers. The resulting damage to the gin bar affects the quality of the cotton fibers by reducing their length.
Gin bar improvements are known wherein a freely rotatable roller disc is attached to the gin bar at the ginning point where fibers are pulled between adjacent gin bars by a rotary saw blade. The roller disc modification has greatly increased the output of the gin stand, while also improving the quality of the cotton by reducing fiber breakage and increasing the staple length.
The beneficial effect of the rotatable gin bar disc is provided by the rotational movement of the roller disc relative to the saw blade. The rolling action of the disc presents an ever-changing shear surface on which the seed and fiber can be pulled apart. The rolling movement of the disc also reduces the tensile forces acting on the cotton fibers, thereby reducing fiber breakage. It is important, therefore, that the roller disc turn freely as the cotton fiber is pulled by the rotatable saw.
The roller discs are press fitted into a sealed ball bearing assembly mounted on the gin bar. A factor which limits usage of the roller disc assembly is that grit, lint and other particulate material tends to accumulate between the inside face of the rotary disc and the stationary structure of the gin bar and the outer race of the annular roller bearing. The build-up of grit, lint and other particulate material restrains the free movement of the roller disc relative to the gin bar, thereby diminishing the beneficial effect of the roller disc. Further build-up of particulate material in the region between the roller disc and the gin bar will arrest movement of the roller disc and may cause seizure of the roller bearings.